Toner for electrostatic image development, electrostatic image developer, toner cartridge, process cartridge, image forming apparatus, and image forming method

Abstract

A toner for electrostatic image development includes: toner particles; perovskite compound particles externally added to the toner particles; and silica particles (S) that are externally added to the toner particles and include an elemental nitrogen-containing compound containing elemental molybdenum and in which the ratio N Mo /N Si of a Net intensity N Mo of elemental molybdenum that is measured by X-ray fluorescence analysis to a Net intensity N Si of elemental silicon that is measured by the X-ray fluorescence analysis is from 0.035 to 0.45 inclusive.

What is claimed is: 
     
         1 . A toner for electrostatic image development comprising:
 toner particles;   perovskite compound particles externally added to the toner particles; and   silica particles (S) that are externally added to the toner particles and include an elemental nitrogen-containing compound containing elemental molybdenum and in which the ratio N Mo /N Si  of a Net intensity N Mo  of elemental molybdenum that is measured by X-ray fluorescence analysis to a Net intensity N Si  of elemental silicon that is measured by the X-ray fluorescence analysis is from 0.035 to 0.45 inclusive.   
     
     
         2 . The toner for electrostatic image development according to  claim 1 , wherein the ratio N Mo /N Si  in the silica particles (S) is from 0.05 to 0.30 inclusive. 
     
     
         3 . The toner for electrostatic image development according to  claim 1 , wherein the total content of the perovskite compound particles and the silica particles (S) is from 0.5 parts by mass to 5.0 parts by mass inclusive based on 100 parts by mass of the toner particles. 
     
     
         4 . The toner for electrostatic image development according to  claim 1 , wherein the mass percentage of the silica particles (S) with respect to the total mass of the perovskite compound particles and the silica particles (S) is from 40% by mass to 60% by mass inclusive. 
     
     
         5 . The toner for electrostatic image development according to  claim 1 , wherein the ratio D2/D1 of an average primary particle diameter D2 of the silica particles (S) to an average primary particle diameter D1 of the perovskite compound particles is from 0.50 to 1.70 inclusive. 
     
     
         6 . The toner for electrostatic image development according to  claim 5 , wherein the average primary particle diameter of the silica particles (S) is from 30 nm to 100 nm inclusive. 
     
     
         7 . The toner for electrostatic image development according to  claim 1 , wherein the silica particles (S) have an average circularity of 0.85 or more. 
     
     
         8 . The toner for electrostatic image development according to  claim 1 , wherein the perovskite compound particles are strontium titanate particles doped with lanthanum. 
     
     
         9 . The toner for electrostatic image development according to  claim 1 , wherein the elemental nitrogen-containing compound containing elemental molybdenum is at least one selected from the group consisting of quaternary ammonium salts containing elemental molybdenum and mixtures of quaternary ammonium salts and metal oxides containing elemental molybdenum. 
     
     
         10 . The toner for electrostatic image development according to  claim 1 , wherein the silica particles (S) are silica particles that include a coating structure formed from a reaction product of a silane coupling agent with the elemental nitrogen-containing compound containing elemental molybdenum adhering to the coating structure. 
     
     
         11 . The toner for electrostatic image development according to  claim 10 , wherein the silane coupling agent contains an alkyltrialkoxysilane. 
     
     
         12 . An electrostatic image developer comprising the toner for electrostatic image development according to  claim 1 . 
     
     
         13 . An electrostatic image developer comprising the toner for electrostatic image development according to  claim 2 . 
     
     
         14 . An electrostatic image developer comprising the toner for electrostatic image development according to  claim 3 . 
     
     
         15 . An electrostatic image developer comprising the toner for electrostatic image development according to  claim 4 . 
     
     
         16 . An electrostatic image developer comprising the toner for electrostatic image development according to  claim 5 . 
     
     
         17 . A toner cartridge detachably attached to an image forming apparatus, the toner cartridge comprising the toner for electrostatic image development according to  claim 1 . 
     
     
         18 . A process cartridge detachably attached to an image forming apparatus, the process cartridge comprising a developing device that houses the electrostatic image developer according to  claim 12  and develops, as a toner image, an electrostatic image formed on a surface of an image holding member with the electrostatic image developer. 
     
     
         19 . An image forming apparatus comprising:
 an image holding member;   a charging device that charges a surface of the image holding member;   an electrostatic image forming device that forms an electrostatic image on the charged surface of the image holding member;   a developing device that houses the electrostatic image developer according to  claim 12  and develops, as a toner image, the electrostatic image formed on the surface of the image holding member with the electrostatic image developer;   a transferring device that transfers the toner image formed on the surface of the image holding member onto a surface of a recording medium; and   a fixing device that fixes the toner image transferred onto the surface of the recording medium.   
     
     
         20 . An image forming method comprising:
 charging a surface of an image holding member;   forming an electrostatic image on the charged surface of the image holding member;   developing, as a toner image, the electrostatic image formed on the surface of the image holding member with the electrostatic image developer according to  claim 12 ;   transferring the toner image formed on the surface of the image holding member onto a surface of a recording medium; and   fixing the toner image transferred onto the surface of the recording medium.